Use of backup power supplies is very important with electronic equipment, especially systems which use memory devices. In particular, systems that include volatile memories or volatile memory devices should be connected to battery backup devices in the event that external power is lost.
When the power supply is interrupted, one or more batteries provide power. In the case of volatile memory devices, it is desired that the power supply provide power at least until the data of the volatile memory device is completely backed up. In an attempt to provide sufficient power to give enough time for backing up volatile memory devices, existing battery backup devices utilize high capacity batteries. Due to the high capacity of the batteries used, power consumption is high and the time required to charge is long. If the batteries are not fully charged when external power is lost, it can lead to complete loss of all power, including backup power, before data backup is complete.